Manaus Airport's Roof Collapsed

As the world cup competition sets to begin on June 12, it as experienced another setbback as the airport in the city of Manaus has its roof collapsed. The collapse which was caused by heavy rainfall and flooding affected parts of the car park, departure and arrival lounges.However, work has commenced to put it back in shape as many of the stadiums that could be used in some other cities are yet to be completed. Authorities said, the kick off still holds on the set date.

2 died in Collapsed Building in Akure

 Early this morning(May 9,2014) around 7am, two(2) people have been confirmed dead after a building under construction collapsed in Akure, Ondo State in Nigeria. The structure came crumbling down as constructions workers on the site resumed for the day's job. Two people died while two others sustained injuries in the incident. 

The Ondo state Commissioner for Housing and Urban Development, Bade Omoloja said, "the building had no approval to begin with because our men at the task force unit of the ministry have been here on two different occasions to stop work. Obviously, very poor quality of work was carried out at the site. There are so many building outside here that doesn't have approvals." 

Eye witnesses say the area is a swampy one and it could be that the foundation of the building was not properly constructed and this led to its collapse.

 

All rescue agencies and the National Emergency Management Authority (NEMA), Nigeria Security and Civil Defence Corps (NSCDC), Nigeria Police Force (NPF), the Red Cross Society of Nigeria, Federal Road Safety Corps (FRSC), State Security Services (SS) were all at the site to help with the rescue.

CHINA OFFERED TO BOOST HOUSING IN NIGERIA WITH $4billion

  Chinese investors have offered the Federal Mortgage Bank of Nigeria $4 billion to boost the nation's housing sector. This was said at the World Economic Forum on Africa going on in Abuja, the nation's capital which opened on Wednesday May 7, 2014 with participants, including Heads of Governments, CEOs of global firms, leading financiers and policy and development technocrats, from over 80 countries attending.


The Managing Director of the Federal Mortgage Bank, Mr Gimba Yau Kumo had said that part of the 200-man Chinese delegation would meet with his management team and other relevant government officials to finally agree on the deal.

Mr Kumo said the management of the Federal Mortgage Bank is also making moves to seek approval of the Federal Government to agree to the terms of the Chinese by discussing with the Minister Of Finance, Dr Okonjo-Iweala

Dampness in Building and its Treatment

Dampness is a problem which affects a very large number of properties. Some people are prepared to live with some degree of dampness, but not to the extent that it can cause problems with health, safety or the integrity of a building and its aesthetics.

 Dampness in a building is caused by various issues which includes condensation, water penetration, plumbing leaks and Rising damps.

Due to rainfall, it is almost impossible to prevent moisture getting into walls, but modern methods which includes chemical DPC`s, use of cement and so on, can prevent moisture in the wall from affecting the surface. The requirements for climate change and the need for thermal efficiency will increasingly be a major cause of internal dampness and condensation in years to come leading to more unnecessary chemical damp courses.

 The source of rising damp is from ground water which is equally able to affect internal and external walls, the bricks and mortar of the walls act like straws enabling the moisture to travel up the walls. A well constructed and maintained building that has an effective physical damp proof course (DPC) is unlikely to suffer rising damp. On the other hand, there are cases where the damp proof course has either failed or become compromised due to age, the use of poor materials for its construction; there could be a  breach in DPC by subsequent construction work to the building,( e.g. the construction of additional wall). External materials such as soil against the external wall above the DPC could cause dampness on the wall.

                                 Treatment For Dampness

When treating  dampness, it is highly advisable to seek professional assistance, this is because  amateur mistakes  may result in unnecessary and costly work which fail to address the damp problem.In cases where the damp proof course has failed it is imperative that corrective measures are taken as quickly as possible. This is because the continued presence of rising damp on walls will result in the dramatic deterioration of brickwork, internal plastering and décor.Affected areas need to be allowed to dry out thoroughly before remedial work is carried out. Treatments suggested for use in modern construction may not be appropriate for traditionally constructed buildings and can make dampness retained within the structure, only for such dampness to begin to show up again in a few years.The course of action commonly involves the installation of a chemical damp proof course. Following this, diligently re-plaster the wall or walls. The plastering process involves a specialist technique which is designed to provide a salt retardant, waterproof render to combat the effect of ground salts in the masonry and also in order to provide a dry internal finish. This finish will then be smoothed over with a top coat skim to provide  smooth surface ready for redecoration.

 The treatment process involves the removal of skirting boards and plaster from the walls. Plaster is usually removed to a height of 1.2 metres. However due to a range of factors, the required height may be increased. Please note that,If the source or cause of the problem is not treated, or the problem is incorrectly diagnosed, the original problem will continue to develop. Hence, the services of a professional is highly recommended.

Cracks in Buildings and Corrective Measures

Cracks in buildings are of common occurrence. Not all cracks should make a building owner panic,but not all cracks should be ignored. A component of a building develops cracks whenever stresses in the component exceed the strength of the component. Stress in a building component could be caused by external or Internal forces. External forces are dead, live, wind,seismic loads or foundation settlement and internal stresses are induced by  thermal movements, moisture changes, chemical action, etc.

 Cracks could be broadly classified as structural and non-structural cracks. Structural Cracks are due to incorrect designs, faulty construction, overloading or inadequate supervision and these may compromise the safety of a building. In a nutshell, structural cracks are directly seen on
 structural members such as beams, columns and slabs .    

Non-structural cracks are mostly due to internally induced stresses in building materials and these generally do not directly result in structural weakening. In course of time, some non-structural cracks may lead to structural cracks due to penetration of moisture through cracks or weathering action, this may result in corrosion of reinforcement and thus may render the structure unsafe.

 Vertical cracks in a long compound wall due to shrinkage or thermal movement is an instance of non-structural cracking. Non-structural cracks normally do not endanger the safety of a building, but may look unsightly or may create the impression of faulty work. If a non-structural crack is ignored, it could pose threat on the safety of the building on the long run.Cracks may vary appreciably in width from very thin hair cracks barely visible to naked eye (about 0.01 mm in width) to gaping cracks 5 mm or more in width. A commonly known classification of cracks, based on their width is:

 a) Thin - less than 1mm in width

 b) Medium - 1 to 2 mm in width
 c) Wide - more than 2 mm in width.

 Cracks could appear in any form, may be of uniform width or may be narrow at one end and thicker at the other end. Cracks could be straight, toothed, stepped, map pattern or random and may be vertical, horizontal or diagonal. Cracks may be only at the surface or may eto more than one layer of materials.Modern structures are comparatively tall and slender, have thin walls that are designed to carry more stress and are built at a fast pace. These structures are therefore, more prone to cracks as compared with old structures, which used to be low, had thick walls, were lightly stressed and were built at a slow pace. Moreover moisture can easily reach the inside of the modern buildings due to the usage of thin walls. Thus measures for control of cracks in buildings assume much greater importance than ever before.

Crack correction

Cracks from different causes have varying characteristics and it is by careful observation of these characteristics that one can correctly diagnose the cause or causes of cracking and adopt appropriate remedial measures. Therefore, the service of a professional is required.On a general note, few basic principles if followed would be very effective

 1.  Rendering of minor crack less that 1m wide may be done after observing the crack for some time and then sealing it with weak mortar of cement, lime and sand. 

 2.   Cracks in which width changes with season should be filled up with elastic fillers like silicon or a polyurethane compound.

 3.     Where shear crack are observed shear keys made of reinforced concrete with at least 1.5 percent steel reinforcement may be provided at 1 to 1.5m intervals.

 4. If cracks are due to movement of soil due to shrinkage and expansion (like in black cotton soil), prevention of moisture penetration in the surrounding areas has to be ensured by providing a waterproof blanket around the plinth. The masonry wall below ground level should also be separated from the adjoining soil by replacing the existing soil with coarse grain material.

Basic Steps in Foundation Construction

It is a known fact that not everyone that invests in the Construction industry knows so much about the construction job.This article assists you from being a novice when your Engineer carries out his activities on your project.After the documentation, in which procedures vary from one locality/region to another, the next thing to be done is to complete the sub structure(foundation) which includes:

1.Site Clearing

 Only on rare occasions would any piece   land be without trees,bushes, grasses etc. Even in some instances a building might have existed on the land and demolished. The trees must be felled and roots grubbed up, bushes and grasses cleared or rubble from the demolished pre-existing building cleared up. All these activities are carried out to ensure a proper and healthy working environment. Removal of top soil is also necessary in situations where the land had bushes and grasses. This is done to a depth of about 150mm (approximately 6 inches). The soil is assumed to be weak and has vegetative materials,also serves as habitat to some micro organism which are not healthy for the foundation of a building.

 2.Excavation

The depth of the excavation is determined by a structural engineer who considers the soil, the frostline(the maximum depth at which soil is frozen) and the height of the water table (the depth in the soil at which you find water). The excavation must be deep enough to place the top of the footing below the frost line. This prevents the concrete from cracking due to the freeze-thaw cycle of the surrounding soil(common in areas with cold climate). The excavation should not be so deep that it would below the water table, because that can cause a chronically wet or flooding to foundation.

3. Footings and Concrete Blinding

Footings are concrete bases that help to spread the weight of the structure from the foundation walls or columns to the surrounding soil. Footings are wider than the foundation walls/columns they support, and form the perimeter of the structure. Sometimes, additional footings are added inside the perimeter to support load-bearing interior walls.Concrete blinding is the process of pouring a thin layer of concrete over the floor of a new building; this can be over the hardcore or over the foundation itself. The purpose of this is to seal in underlying material and prevent dirt and mud from interfering with the structure.

4 Walls

Foundation wall thickness is determined by a structural engineer who considers the height of the wall and the load it will be able to carry conveniently. (Structural load is the force or combination of forces of gravity, wind, and earth that act on the structural system of a building). Wall thickness varies from structure to structure, and even within a building

5 Filling, Backfill and Hardcore

Filling the foundation is another important aspect that requires adequate attention as the materials to be used to fill the foundation will depend on the condition of the site with is to be determined by a professional. While  backfilling  is pushing into the trenches the materials that was excavated from the foundation,it is recommended that it should be soil that drains easily. Apart from burying a portion or all of the walls below the surface,it also provides ideal stability needed by the foundation. After the foundation has been filled reasonably and well compacted, hardcore (sizes between 75mm and 300mm) are placed and compacted.

6 Dampproofing and Waterproofing

Dampproofing and waterproofing are usually mistaken for each other but they literally mean different things(read more in the article 'Dampness in Building and its Prevention').  A damp proof course is a course of some impermeable material laid in the foundation walls of building near the ground to prevent dampness from rising into the building. It is a horizontal barrier in a wall designed to prevent moisture rising through the structure by capillary action.

7. Concrete Reinforcement-Wire Mesh

This is placed strategically to ensure that there's no continuous cracking of concrete slab. It is also referred to as thermal reinforcement

8. Oversite Concrete (german floor)

This is a 4-inch to 6-inch thick concrete carefully placed and in a mixing ratio that will be specified by the Engineer.

How To Effectively Build On A Swampy Land

Swamps are forested wetlands. Like marshes, they are often found near rivers or lakes and have mineral soil that drains very slowly. They have trees and bushes. They may have water in them for the whole year or for only a part of the year.

 Lots of developers try to avoid constructing on swampy land because of the cost of getting it right but in areas like Lagos state where it is increasingly getting difficult to get dry plots of land, swamps or waterlogged plots are inevitable. Places like Lekki and Ajah were swamps that have been turned residential neighborhood with massive constructions. Sometimes, it is ignorance or naivety that gets people to spend unnecessary sum of money.  Therefore, to construct on swampy land, it is important you employ the services of relevant professionals. The professional would know procedures, engineering methods and techniques to take to ensure that the development is perfect. Because the construction of houses on swamps require special attention, either the soil is removed or  strengthened by suitable means known as stabilization after ascertaining its (soil) properties through thorough investigations. These investigations are done so as select the appropriate type of foundation for the structure.

As a Civil Engineer,I will advise those who have bought swampy land to ensure that the foundations of their buildings rest on sound soil so that when the super structure (building) is completed, the weight would be evenly spread.

On how to effectively utilise a swampy land, building on swampy land requires thorough soil investigation as mentioned earlier, this goes a long way to reveal so many things as regards the soil properties and this is a major factor to the choice of foundation to be used. It is generally assumed that the only suitable foundation for swamp is raft. From a professional's point of view, I can categorically say that sometimes, the swamp might be too deep that using the raft foundation will not solve the problem. In that case, you should go for a pile foundation,” - which are of two types (end-bearing pile foundation and friction pile foundation.).

It is also important to inform that the type of filling done before doing the foundation matters a great deal, the swampy land should be sand-filled so that it would become firm (some would want to use laterite, but consult an expert before the choice of material is made).
Builders on swampy soil should equally consider the future level of the road around the premises. If the road level is higher than the level of the foundation, the house will have drainage challenge. Water from the ground will also pose a challenge to the building, this is why from the onset, the developer should use water resisting membrane so as to prevent dampness of the walls.

In constructing the fence round the building, concrete retaining wall must be used on the lower part of the fence above the proper floor level.

Finally,  painting of the external walls of the structure should be done with premium quality paint to prevent moisture on the building